Tail skid



R. 'L MARKEY lJuly 15, 1930.

TAIL SKID Filed Aug. 30, 1928 2 Sheets-Sheet l July 15, 1930. R, MARKEY 1,770,756

TAIL SKI D Filed Aug. 50, 1928 2 Sheets-Sheet y2l gnou/woz Patented July 15,' 1930 y UNITED sTATEs l PATENT OFFICE ROSOOE I. MARKEY, OF BUFFALO, NEW YORK, ASSIGNOR OF ONE-HALF TO FAIRCHILD AVIATION CORPORATION, OF NEW YORK. N. Y., A CORPORATION OF DELAWARE TAIL SKID Application med August 80, 1928. Serial No. 802,911.

This invention relates to aeroplanes in general and particularly to a new and improved landing means.

One object of the present invention is to provide an improved form of tail skid which 1s equipped with shock absorbers and also with a wheel and a replaceable shoe.

Another object of this invention is to provide a tail skid which is capable of adjusting 1o itself to conform to the dlrection of motion of the tail of the aeroplane to which it is attached. j s

' It is usual 'in the construction of land types of aeroplanes to provide a suitable tail skid 'for the purpose of preventing the tail of the aeroplane from dragging on the ground during landing and taking Lolf operations and thus preventing serious injury of the rudders which are mounted on the tail.

Up to the present timeV the tail skids in common use have consisted of a simpleshoe mounted on the end of a member pivoted or rigidly seculred to the tail'of the aeroplane and have sometimes been equipped with zshock absorbers for the purpose of reducing the damaging effect of landing shocks. Such' tail skids have been open to the objection that'on hard ground excessive friction between the shoe and the ground caused con- 5o siderable wear on the shoe while in landing,

J on soft ground the skid shoe would frequently sink in permitting the tail to strike the ground and damage the rudders.

Another objectionable feature of the com- :5 mon types o-f tail skid is that the friction developed between the sh'oe and the ground makes it dificult to maneuver a plane on the surface of the ground either under'` the power supplied by the engine ormanually such as o in wheeling the aeroplane from its hangar or irlf bringing it into'position ready for a take-` It is the principal object of the present invention to provide a new and improved form 5 of tail skid which has none of the disadvanf tages of the various types of tail skid in present use and ywhich is simple and rugged inI construction, is easily attached or removed from the tail of the aero lane, and has few 0 working parts. @ther o jects and advanvextending bracing members which j tages of the present invention will be apparfuselage 'frame of which two are provided as a rule and extend lengthwise of the fuselage. The numerals 2 and 3 represent vertically join the lower longrons 1 of the fuselage to the upper longrons (not shown).

Pi'voted between .ears 4 formed integral with or suitably secured to the bracing members 2 at each side of the fuselage is a mov-v able frame in which the tail skid proper is mounted. The 'frame consists of two side members 5 which are joined together by crosspieces 6, 7, and 8, the cross piece 6 being somewhat longer than the cross-pieces 7 and 8, and is pivotally mounted in the ears 4 so that the, entire frame is adapted to swing about the cross-piece 6 as an axis. ing members 9 joined to the side members 5 serve to support a cup-shaped 4member 10. The side members 5 are not parallel to each other but taper towards each other in a `direction opposite to the pivot member 6 and are provided with plates 11 which also tapery towardseach other so as to form a nose to of the Upwardly proj ectwhich is pivoted the lower end of a shock E absorber.

The shock absorber, as shown in Figs. 2 l

and consists of a member 12 composed of drical surfape of the member 12 is a plunger f 13 which is provided withf an enlargement at its end which just ts 'the inside surface of -a short length of tubing onetend of which is its general construction lto the member 12 and is fastened within the member 14 b y means of a pin passing through the member 14 and the plunger 13 or by other suitable means. The member 14 is pivotedto a cap welded or otherwise fastened to the vertical bracing member 3, which forms part of the frame of the fuselage. Both of the members 12 and -14 are provided with suitable flanges 15 and 16 which may be welded or screwed in any suitable manner to the members 12 and 14. Interposed between the flanges 15 and 16 are resilient rings 17 which may be composed of rubber or other suitable resilientl material or, if so desired, an Ordinary coil spring of suitable size may be substituted for the rings 17. For thepurpose of preventing the parts justdescribed from becoming displaced from their working positions while the aeroplane is in Hight, the plunger 13 is provided with a second enlargement or shoulder 18 which normally abuts against a fiange or circular plate 19 which may be screwed or riveted to the flange 15 of member 12. This construction permits the free compression of the rings 17 but prevents the plunger 13 from being withdrawn from the member 12.

` The lower end of the cylindrical member 12 is closed and a cap opening 20 is provided for the purpose of injecting lubricant by means of a suitable pressure lubricator such as a grease gun. The return of plunger 13 when the load is removed from shock absorbingA unit 17 may be cushioned by a resilient washer. Y

The skid proper consists of a curved member 21 which has the general sha e shown in Fig. 3, being constructed of tu ing bent in the manner shown', to which is attached a replaceable shoe to be described hereinafter. The upper end ofthe member 21 projects through the cup-shaped member '10 and is held out of Contact with the walls of the cupshaped member by means of a ring 22 of rubber or other suitable resilient material fitting snugly within the cup-shaped member. As will be noted from a study of Fig. 2 there is considerable clearance rovided between the member 21 and the wal s of the hole through the bottom of the cup-shaped member 10 in order to permit more or lesstransverse movement of the member 21 in response to shocks transmitted `to the skid when landing the aeroplane on the ground, such movement 'being resisted by the resilient'material coinprising the ring 22.

Mounted about midway'between y.the ends of the member 21 is a spherically shaped'A member 23 which is held in place by means of A suitable screws the heads of which are sunk within the member 23 or, if desired by means bers 24, 25, provided with openings thru which passes the member 21, are clamped together over the spherically sha ed member 23 so that the member 23 and t e members y24, 25 form a universal oint, an effect which permits the movement of the upper end of the member 21 in all directions subject to the restraining action of the resilient ring 22. The hemispherical member 25 is clamped to lugs 26 carried by the side members 5 and also to the cross piece 8 by means of the same bolts holding the members 24 and 25 together. I do not desire to limit myself in this respect.

Attached to the lower end of the skid21 is a detachable shoe 27 which is provided with lugs 28 and 29 and also with a cutout portion 30. Welded or otherwise fastened to the lower end of the member 21 on the inside of the curve is a short piece of tubing 31 just long enough to fit between the lugs 28. Also welded or otherwise fastened to the lower end' of the member 21 are two lugs 32, the holes of which are adapted to coincide with the similar holes in the lugs 29. Suitable bolts the member 21 from sinking into soft ground. d

The cutout portion 30 formed in the shoe 27 is adapted to receive a wheel 33 which is provided with an axle 34 passing through holes 35 in flanges formed integral with or suitably secured to the shoe just adjacent to the cutout portion 30. An arm 36 mounted upon the upperend of the member 21 is connected by means of a resilient cable 37 to the cross piece 6. vThe .cable 37 `tends to return the parts when displaced to the position shown in Fig. 2 with the axis of the wheel transverse to the axis of the tail of the aeroplane.

A cavity may be formed withinfthe wheel 33 to serve as an oil reservoir to lubricate the bearing on axle 34. Felt washers held in metallic cupsv may protect this bearing from grit to prevent wear. The tread of wheel 33 and lower surface of shoe 27 may be specially treated or coated to increase its wearing quality. f

The wheel 33 projects below the level of the skid shoe 27 and in landing uponhard tentthus preventing excessive wear on 4the y shoe 27 and at the same time' permittin I easier handling of the machine. .The broa construction of the surface ofthelshoe permits landing -on soft ground without sinkying into the mud. with the damage that usually'results when the ordinary type of skids are used. The shock absorber mechanism comprised by the members 12 and-14 'said supporting means, said shoc and their associated parts takes up the greater ortion of the shock transmitted to the mem er 21 in landing while the remain-l der is absorbed by the resilient material in the ring 22 within the cup-shaped member 10. `In executing a sharp? turn the member 21 will be turned within the joint formed by the members 24 and 25 so as to permit the tail to move over such slight obstructions as ruts or stones present on the landing field while the resilient cable 37 will tend to restore the member 21 to its proper position with the axis of the wheel transverse to the axis of the tail of theaeroplane after the turn is completed.- A very distinct advantage of the present inventiaon is that it greatly reduces the effort required to' wheel an aeroplane to which it is attached into po` sition on the landing field or into and out of the hangar and permits exceptionally easy handling of the machine under its own power as well as by hand upon the landing field.

Various changes in the construction of the embodimenth illustrated in the drawings ma be made without departing from the spint ofthe invention, and I do not desire to limit myself tothe specific construction shown and described, but to interpret the invention broadly within the scope of the appended claims. What I claim as my invention is: 1. In a tailskid for bination of a pivoted tail skid support, a tail skid pivotally mounted in said su port by means of a universal mountin a s ock absorbing means for said tail ski support, and independent shock absorbing means for said tail skid.

2. In a tail skid for aeroplanes, the combination of a tail skid support, a tail skid pivotally mounted in said support by means of a universal mounting, a shock absorbing means for said tail skid support, and independent shock absorbing-means for said tail skid, a detachable shoe for said tail skid adapted to revent said tail skid from sinking into so ound, and a wheel mounted on said shoe or permitting the tail skid to move over hard ground. V

.3. In a tail skid foraeroplanes, the combination of a iiexibly mounted skid member, shock absorbing means for said skid member, a pivoted supporting means for said skid member, and shock absorbin means for absorbing means being independent in their actions.

4. In a tail skidfor aeroplanes, the combinaton of a skid member, su

porting means for vsaid skid member, shock a sorbing means for said sln'd member, a ivoted supporting means for said skid mem er, and shock absorbing means for said supporting means, said shock absorbing means bein independent in'their actions, a detachab said skid member, a wheel mounted'on said aeroplanes, the come shoe for shoe, and separate shock absorbing means for said skid member and said supporting means.

5. In a tail skid for aero lanes, the combi- ROSCOE I. MARKEY.

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